Tubular writing pen



April 29, 1969 H MPE 3,441,354

TUBULAR WRITING PEN Filed Jan. 16, 1967 United States Patent Office 3,441,354 Patented Apr. 29, 1969 3,441,354 TUBULAR WRITING PEN Helmuth Riepe, Hamburg, Germany, assignor, by mesne assignments, to Rapidograph, Inc., Bloomsbury, NJ., a corporation of New Jersey Filed Jan. 16, 1967, Ser. No. 609,370 Claims priority, application Germany, Jan. 22, 1966,

Inf. C1. Bsk 5/.06

U.S. Cl. 401-182 4 Claims ABSTRACT 0F THE DISCLOSURE The present invention relates to a writing pen comprising a barrel forming a main ink reservoir, a Writing head fixed in the open end of the barrrel, a sealing piston slidably contained in the front half of the barrel relative to the open end thereof, a rod attached to the back of the piston and contained in the hear half of the barrel, a retractable actuating plunger and a releasable coupling means for coupling the rod and plunger when the plunger is in an extended position, whereby the pen may be filled with ink by drawing it in by withdrawal of the piston from a forward position in the front half of the barrel.

Background Og the invention Tube writing pens which are used as drawing implements, and which comprise a barrel with a tube witing head inserted or screwed into the same, are filled with ink by first unscrewing the tube writing head, dropping the ink into the open main ink reservoir and then screwing the tube writing head back into place.

It was hitherto thought necessary to provide such simple ink reservoirs because a lfountain pen filling mechanism, such as one comprising pistons that move by rotation, may cause trouble by virtue of the ink drying out. On the other hand, conventional tube writing pens which are filled by first unscrewing the writing head have the drawback that some of the ink is squeezed out of the ink reservoir when the Writing head is replaced, thus causing unnecessary spillage and loss of ink. Moreover, in the venting channel which is present in a tube writing pen, ink residues may readily form incrustations which block the channel and prevent a proper equalization of pressures, so that the flow of ink becomes irregular or the ink continues to dribble after the pen has been lifted oi the paper.

According to the present invention, there is provided a Writing pen comprising a barrel forming a main ink reservoir, a writing head fixed in the open end of the barrel, a sealing piston slidably contained in the front half of the barrel relative to the open end thereof, a rod attached to the back of the piston and contained in the rear half of the barrel, a retractable actuating plunger and a releasable coupling means for coupling the rod and plunger when the plunger is in an extended position.

This arrangement permits the pen to be filled with ink by drawing it in by Withdrawal of the piston after the actuating plunger has been retracted from the barrel and the piston pushed forwards with its aid. Any residues of ink can thus be loosened or flushed out by moving the piston to and fro.

Summary of the invention In the filling mechanism, there is preferably a constriction between the front half of the barrel forming the ink reservoir and the rear half containing the piston rod for arresting the piston. Moreover, the plunger may be arranged in its retracted position, to be coupled to the sleeve, for instance by a friction means.

Such an arrangement Will, therefore, permit the actuating plunger to be retracted until it engages the sleeve and then to be pushed forwards together with the pistou rod and the piston which is attached to the rod, which may be hollow and thus be, in effect, a sleeve. By then retracting the piston, ink can be drawn into the forward part of the barrel. After release of the coupling between the actuating plunger and the sleeve, the actuating plunger can then be returned into the sleeve without entraining the piston.

However, the preferred coupling arrangement is in the form of an actuating plunger which is hollow throughout its length, and which at its forward end, forms a wider diameter chamber, the piston rod or sleeve being slidably contained in the plunger and provided at its rearward end with a slotted projecting cylindrical flange, the arrangement being such that according to the position of a stepped ring ontained in the chamber, the cylindrical shoulder will be either intercepted by a shoulder formed by the step between the chamber and the remainder of the hollow interior of the plunger or slide into said hollow interior.

Brief description of the drawings In order to enable the invention to be more readily understood, reference will now be made to the accompanying drawings, which illustrate diagrammatically and by way of example, an embodiment thereof, and in which:

FIG. l is a section of a tube writing pen in its normal position.

FIG. 2 is a section of the barrel, showing an actuating plunger retracted.

FIG. 3 is an analogous section to FIG. 2, showing a piston in its forward position shortly before its retraction.

FIGS. 4a and 4b are fragmentary sections of the bottom end of the actuating plunger, shown on a larger scale.

Description of the preferred embodiment The tube writing pen illustrated in the drawings comprises a tube writing head 2 which can be inserted or threadedly fitted into the opening 3 of a barrel 4. The forward portion of the barrel 4 forms an ink reservoir 5 which is rearwardly closed by a piston 6. The piston 6 is attached to a rod 7 which is freely movable in the rearward half 8 of the barrel and which slidably carries an actuating plunger 9. The two halves of the barrel are separated by a constriction 10 between the ink reservoir 5 and the rearward chamber 8, the constriction forming a stop cooperating with the rear face of the piston.

The rod 7 and the actuating plunger 9 are coupled together by coupling means. The actuating plunger 9 is of hollow construction throughout as indicated by 12 and has an enlarged diameter chamber 13 at its forward end. The extreme end of this chamber is closed by an annular shoulder 11 having an internal diameter suitably chosen for the rod 7 to be freely moved to and fro. The right hand end of the chamber is bounded by an annular shoulder 17 which forms a step between the chamber and the remainder of the hollow plunger interior 12. The end of the piston rod is slotted as shown at 14, and has a projecting cylindrical flange 15. The chamber also contains a stepped ring 16 which may also be referred to as a slide-over sleeve. The position of this ring and the springiness of the slotted projecting cylindrical flange 15 enable the latter to be coupled to the plunger by engaging the shoulder 17 between the chamber and the remaining hollow interior of the plunger, whereas the coupling is released -when the slide-over sleeve 16 compresses the slotted projecting flange and thus allows the entire piston rod 7 to enter the hollow interior 12 of the plunger.

In position of rest, as shown in FIG. l, the actuating plunger 9 is pushed down over the piston rod 7. If it is now desired to push the piston forwards for filling the ink reservoir, the actuating plunger 9 must rstrberetracted. When the projecting flange enters the chamber 13, the slot 14 opens by spring action and the flange 15 snaps under the annular shoulder 17. In this position which is shown in FIG. 2, the piston can be pushed downwards.

When the piston is retracted, the slide-over sleeve 16 is forced by the terminal shoulder 11, to ride over the projecting cylindrical flange 15 to the extent the step 18 in the slide-over sleeve 16, permits the sleeve to be thus displaced. When the piston 6 has drawn in suicient ink and bears against the constriction 10, the slide-over sleeve will be in the position shown in FIG. 4a. The actuating plunger 9 can then be pushed back into the barrel without moving the piston because during this movement the slide-over sleeve will simply move on the flange from the position shown in FIG. 4a into the position shown in FIG. 4b, in which the slightly compressed piston rod can slide out of the -slide-over sleeve 16 into the hollow interior 12 of the rear end of the plunger.

The entire Ifilling operation or the operation of flushing the tube writing pen by repeatedly drawing in and ejecting water or ink can be quickly performed without any diiliculty. 'Ihe lling mechanism is so contrived that for filling the pen, the piston need be reciprocated only once and the actuating plunger then pushed back into the barrel. No additional threads are, therefore needed. Naturally, the present filling mechanism could also be used with advantage in self-filling writing pens of other kinds.

Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be made within the spirit of the invention and scope of the appended claims.

lWhat I claim is:

1. A writing pen comprising a barrel (4) having an open end (3) and a radially inwardly extending constriction (10) dividing said barrel into two halves dening a main ink reservoir (5) extending inwardly from the open end and a rear-ward chamber (8), a writing head (2) fixed in said open end, a piston (6) slidably contained in said main ink reservoir, a rod (7) attached to the back of said piston extending therefrom and into said rearward chamber and freely movable therein, a retractable actuating plunger-(9) in externally disposed'telescopic engagement with said rod and substantially co-extensive with the distance between the lowermost and uppermost positions of said piston, and releasable coupling means for coupling the rod and said plunger in sole dependence upon the axial movement thereof when the plunger is in an extended position, and for decoupling saidrod and said plunger in sole dependence upon the axial movement thereof when said plunger is ina vretracted position, whereby when said plunger is in an extended position it will serve as an extension of said rod to facilitate up and down movement of said piston within said main ink reservoir.

2. A Writing pen as claimed in claim 1, wherein the actuating plunger (9) is hollow throughout its length and contains a larger diameter chamber at' its front end, wherein the rod (7 which at its rearward end is slotted and formed with a projecting cylindrical ange (15), is slidably movable inside said plunger, and wherein a stepped ring (16) is movable from a first position where the cylindrical flange engages a shoulder between the chamber and the remaining hollow interior of the actuating plunger when this is retracted and coupled, to a secondv position where the stepped ring slides into said hollow interior.

3. A writing pen as claimed in claim 1, said constriction serving as a stop for the piston and also for additionally sealing the ink reservoir.

4. A writing pen as claimed in claim 2, said constriction serving as a stop for the piston and also for additionally sealing the ink reservoir.

References Cited UNITED STATES PATENTS 1,395,878 ll/l92l Upton 401-182 1,445,900 2/1923 McKay 401-182 1,648,241 11/1927 Poetz 401-182 FOREIGN PATENTS 1,062,762 12/1953 France'. 373,590 7/1939 Italy.

LAWRENCE CHARLES, Primary Examiner. 

